code: def testTwo(self):
      signal = [-1.156, 0]
      self.assertAlmostEqualVector(
          PowerSpectrum()(signal),
          [x**2 for x in Spectrum()(signal)],
          1e-6,
      )
  
file_path: essentia/test/src/unittests/standard/test_powerspectrum.py
imports: from essentia_test import *
label_desc: Use image node_id 4 for calling the TestPowerSpectrum obj's underlying member method code with example usage: obj.testTwo() without return types